diff options
| -rw-r--r-- | Documentation/filesystems/nfs/nfsroot.txt | 35 | ||||
| -rw-r--r-- | net/ipv4/ipconfig.c | 118 |
2 files changed, 136 insertions, 17 deletions
diff --git a/Documentation/filesystems/nfs/nfsroot.txt b/Documentation/filesystems/nfs/nfsroot.txt index a1030bea60d3..d2963123eb1c 100644 --- a/Documentation/filesystems/nfs/nfsroot.txt +++ b/Documentation/filesystems/nfs/nfsroot.txt @@ -5,6 +5,7 @@ Written 1996 by Gero Kuhlmann <gero@gkminix.han.de> Updated 1997 by Martin Mares <mj@atrey.karlin.mff.cuni.cz> Updated 2006 by Nico Schottelius <nico-kernel-nfsroot@schottelius.org> Updated 2006 by Horms <horms@verge.net.au> +Updated 2018 by Chris Novakovic <chris@chrisn.me.uk> @@ -79,7 +80,7 @@ nfsroot=[<server-ip>:]<root-dir>[,<nfs-options>] ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>: - <dns0-ip>:<dns1-ip> + <dns0-ip>:<dns1-ip>:<ntp0-ip> This parameter tells the kernel how to configure IP addresses of devices and also how to set up the IP routing table. It was originally called @@ -178,9 +179,18 @@ ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>: <dns1-ip> IP address of secondary nameserver. See <dns0-ip>. - After configuration (whether manual or automatic) is complete, a file is - created at /proc/net/pnp in the following format; lines are omitted if - their respective value is empty following configuration. + <ntp0-ip> IP address of a Network Time Protocol (NTP) server. + Value is exported to /proc/net/ipconfig/ntp_servers, but is + otherwise unused (see below). + + Default: None if not using autoconfiguration; determined + automatically if using autoconfiguration. + + After configuration (whether manual or automatic) is complete, two files + are created in the following format; lines are omitted if their respective + value is empty following configuration: + + - /proc/net/pnp: #PROTO: <DHCP|BOOTP|RARP|MANUAL> (depending on configuration method) domain <dns-domain> (if autoconfigured, the DNS domain) @@ -189,13 +199,26 @@ ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>: nameserver <dns2-ip> (tertiary name server IP) bootserver <server-ip> (NFS server IP) - <dns-domain> and <dns2-ip> are requested during autoconfiguration; they - cannot be specified as part of the "ip=" kernel command line parameter. + - /proc/net/ipconfig/ntp_servers: + + <ntp0-ip> (NTP server IP) + <ntp1-ip> (NTP server IP) + <ntp2-ip> (NTP server IP) + + <dns-domain> and <dns2-ip> (in /proc/net/pnp) and <ntp1-ip> and <ntp2-ip> + (in /proc/net/ipconfig/ntp_servers) are requested during autoconfiguration; + they cannot be specified as part of the "ip=" kernel command line parameter. Because the "domain" and "nameserver" options are recognised by DNS resolvers, /etc/resolv.conf is often linked to /proc/net/pnp on systems that use an NFS root filesystem. + Note that the kernel will not synchronise the system time with any NTP + servers it discovers; this is the responsibility of a user space process + (e.g. an initrd/initramfs script that passes the IP addresses listed in + /proc/net/ipconfig/ntp_servers to an NTP client before mounting the real + root filesystem if it is on NFS). + nfsrootdebug diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c index 9abf833f3a99..d839d74853fc 100644 --- a/net/ipv4/ipconfig.c +++ b/net/ipv4/ipconfig.c @@ -28,6 +28,9 @@ * * Multiple Nameservers in /proc/net/pnp * -- Josef Siemes <jsiemes@web.de>, Aug 2002 + * + * NTP servers in /proc/net/ipconfig/ntp_servers + * -- Chris Novakovic <chris@chrisn.me.uk>, April 2018 */ #include <linux/types.h> @@ -93,6 +96,7 @@ #define CONF_TIMEOUT_MAX (HZ*30) /* Maximum allowed timeout */ #define CONF_NAMESERVERS_MAX 3 /* Maximum number of nameservers - '3' from resolv.h */ +#define CONF_NTP_SERVERS_MAX 3 /* Maximum number of NTP servers */ #define NONE cpu_to_be32(INADDR_NONE) #define ANY cpu_to_be32(INADDR_ANY) @@ -152,6 +156,7 @@ static int ic_proto_used; /* Protocol used, if any */ #define ic_proto_used 0 #endif static __be32 ic_nameservers[CONF_NAMESERVERS_MAX]; /* DNS Server IP addresses */ +static __be32 ic_ntp_servers[CONF_NTP_SERVERS_MAX]; /* NTP server IP addresses */ static u8 ic_domain[64]; /* DNS (not NIS) domain name */ /* @@ -579,6 +584,15 @@ static inline void __init ic_nameservers_predef(void) ic_nameservers[i] = NONE; } +/* Predefine NTP servers */ +static inline void __init ic_ntp_servers_predef(void) +{ + int i; + + for (i = 0; i < CONF_NTP_SERVERS_MAX; i++) + ic_ntp_servers[i] = NONE; +} + /* * DHCP/BOOTP support. */ @@ -674,6 +688,7 @@ ic_dhcp_init_options(u8 *options, struct ic_device *d) 17, /* Boot path */ 26, /* MTU */ 40, /* NIS domain name */ + 42, /* NTP servers */ }; *e++ = 55; /* Parameter request list */ @@ -753,12 +768,13 @@ static void __init ic_bootp_init_ext(u8 *e) */ static inline void __init ic_bootp_init(void) { - /* Re-initialise all name servers to NONE, in case any were set via the - * "ip=" or "nfsaddrs=" kernel command line parameters: any IP addresses - * specified there will already have been decoded but are no longer - * needed + /* Re-initialise all name servers and NTP servers to NONE, in case any + * were set via the "ip=" or "nfsaddrs=" kernel command line parameters: + * any IP addresses specified there will already have been decoded but + * are no longer needed */ ic_nameservers_predef(); + ic_ntp_servers_predef(); dev_add_pack(&bootp_packet_type); } @@ -922,6 +938,15 @@ static void __init ic_do_bootp_ext(u8 *ext) ic_bootp_string(utsname()->domainname, ext+1, *ext, __NEW_UTS_LEN); break; + case 42: /* NTP servers */ + servers = *ext / 4; + if (servers > CONF_NTP_SERVERS_MAX) + servers = CONF_NTP_SERVERS_MAX; + for (i = 0; i < servers; i++) { + if (ic_ntp_servers[i] == NONE) + memcpy(&ic_ntp_servers[i], ext+1+4*i, 4); + } + break; } } @@ -1268,6 +1293,7 @@ static int __init ic_dynamic(void) #ifdef CONFIG_PROC_FS +/* Name servers: */ static int pnp_seq_show(struct seq_file *seq, void *v) { int i; @@ -1306,7 +1332,7 @@ static const struct file_operations pnp_seq_fops = { }; /* Create the /proc/net/ipconfig directory */ -static int ipconfig_proc_net_init(void) +static int __init ipconfig_proc_net_init(void) { ipconfig_dir = proc_net_mkdir(&init_net, "ipconfig", init_net.proc_net); if (!ipconfig_dir) @@ -1314,6 +1340,52 @@ static int ipconfig_proc_net_init(void) return 0; } + +/* Create a new file under /proc/net/ipconfig */ +static int ipconfig_proc_net_create(const char *name, + const struct file_operations *fops) +{ + char *pname; + struct proc_dir_entry *p; + + if (!ipconfig_dir) + return -ENOMEM; + + pname = kasprintf(GFP_KERNEL, "%s%s", "ipconfig/", name); + if (!pname) + return -ENOMEM; + + p = proc_create(pname, 0444, init_net.proc_net, fops); + kfree(pname); + if (!p) + return -ENOMEM; + + return 0; +} + +/* Write NTP server IP addresses to /proc/net/ipconfig/ntp_servers */ +static int ntp_servers_seq_show(struct seq_file *seq, void *v) +{ + int i; + + for (i = 0; i < CONF_NTP_SERVERS_MAX; i++) { + if (ic_ntp_servers[i] != NONE) + seq_printf(seq, "%pI4\n", &ic_ntp_servers[i]); + } + return 0; +} + +static int ntp_servers_seq_open(struct inode *inode, struct file *file) +{ + return single_open(file, ntp_servers_seq_show, NULL); +} + +static const struct file_operations ntp_servers_seq_fops = { + .open = ntp_servers_seq_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; #endif /* CONFIG_PROC_FS */ /* @@ -1388,17 +1460,20 @@ static int __init ip_auto_config(void) int err; unsigned int i; - /* Initialise all name servers to NONE (but only if the "ip=" or - * "nfsaddrs=" kernel command line parameters weren't decoded, otherwise - * we'll overwrite the IP addresses specified there) + /* Initialise all name servers and NTP servers to NONE (but only if the + * "ip=" or "nfsaddrs=" kernel command line parameters weren't decoded, + * otherwise we'll overwrite the IP addresses specified there) */ - if (ic_set_manually == 0) + if (ic_set_manually == 0) { ic_nameservers_predef(); + ic_ntp_servers_predef(); + } #ifdef CONFIG_PROC_FS proc_create("pnp", 0444, init_net.proc_net, &pnp_seq_fops); - ipconfig_proc_net_init(); + if (ipconfig_proc_net_init() == 0) + ipconfig_proc_net_create("ntp_servers", &ntp_servers_seq_fops); #endif /* CONFIG_PROC_FS */ if (!ic_enable) @@ -1523,6 +1598,19 @@ static int __init ip_auto_config(void) if (i + 1 == CONF_NAMESERVERS_MAX) pr_cont("\n"); } + /* NTP servers (if any): */ + for (i = 0; i < CONF_NTP_SERVERS_MAX; i++) { + if (ic_ntp_servers[i] != NONE) { + if (i == 0) + pr_info(" ntpserver%u=%pI4", + i, &ic_ntp_servers[i]); + else + pr_cont(", ntpserver%u=%pI4", + i, &ic_ntp_servers[i]); + } + if (i + 1 == CONF_NTP_SERVERS_MAX) + pr_cont("\n"); + } #endif /* !SILENT */ /* @@ -1620,8 +1708,9 @@ static int __init ip_auto_config_setup(char *addrs) return 1; } - /* Initialise all name servers to NONE */ + /* Initialise all name servers and NTP servers to NONE */ ic_nameservers_predef(); + ic_ntp_servers_predef(); /* Parse string for static IP assignment. */ ip = addrs; @@ -1680,6 +1769,13 @@ static int __init ip_auto_config_setup(char *addrs) ic_nameservers[1] = NONE; } break; + case 9: + if (CONF_NTP_SERVERS_MAX >= 1) { + ic_ntp_servers[0] = in_aton(ip); + if (ic_ntp_servers[0] == ANY) + ic_ntp_servers[0] = NONE; + } + break; } } ip = cp; |